2 cups tri-sodium phosphate (TSP)
1 bucket water
Mix and let set overnight to dissolve. Apply liberally to floor with a scrub brush. Let set 10 to 15 minutes, then scrub vigorously with an abrasive cleaning pad. Mop with clean water and let dry.
[color=990000]CAUTION:[/color]
When working with this solution, always wear rubber gloves, eye goggles, and loose clothing.